Journal of Oral & Facial Pain and Headache, 03/2001

Aims: To study the effect of experimentally induced osteoarthrosis, or non-inflammatory degenerative changes, on the innervation of the sheep temporomandibular joint (TMJ) through the use of indirect immunohistochemistry and image analysis quantification. Methods: Bilateral condylar scarification was performed in 8 sheep, which were killed at 16 weeks post-operation; 3 unoperated sheep served as controls. Tissues from 8 osteoarthrotic joints and 4 control joints were processed for the immunostaining with antisera for protein gene product 9.5 (PGP 9.5), substance P (SP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and tyrosine hydroxylase (TH). An additional 10 joints were decalcified to study the morphologic changes induced by the condylar abrasion. Results: Osteoarthrotic changes were commonly seen in the anterior and lateral regions of the joint and included fibrosis, peripheral osteophyte formation, cysts, and erosion of articular surfaces. In the osteoarthrotic joints, the distribution of PGP 9.5-, CGRP-, and SP-immunoreactive (IR) nerve fibers was similar to that observed for control joints in the capsule, synovium, and capsule/disc junction. There were statistically detectable decreases in the percent surface area of IR nerve fibers in the capsule for both PGP 9.5 and CGRP in arthrotic joints compared with control joints. The lateral and anterior regions of the capsule had greater density of PGP 9.5- and CGRP-IR nerve fibers than other parts of the capsule in both control and arthrotic joints, and the medial capsule was poorly innervated in all joints. Immunostaining for substance P was always weaker. Conclusion: This study suggests that while inflammatory arthritis has a marked influence on the density of sensory and autonomic nerve fibers in synovium in a variety of joints in different species, experimentally induced non-inflammatory osteoarthrosis in the sheep TMJ also leads to a depletion of the density of nerve fibers in the capsule, especially in the lateral part of the joint. Further work is required to determine whether other parts of the joint, such as synovium and marrow, respond differently to experimentally induced osteoarthrosis. Keywords: calcitonin gene-related peptide, substance P, protein gene product 9.5, neuropeptide Y, nerve fibers, temporomandibular joint, osteoarthrosis

Aims: To examine the influence of psychosocial functioning and dental factors in adolescents with temporomandibular disorders (TMD) versus healthy subjects. Methods: The TMD sample comprised 63 patients (21 boys and 42 girls, 33% and 67%, respectively, with a mean age of 14.9 years; range 12 to 18 years) and was compared with 64 healthy control subjects (17 boys and 47 girls, 27% and 73%, respectively, with a mean age of 14.8 years). Subjects in the TMD group had to report pain once a week or more and to have a TMD pain diagnosis according to the Research Diagnostic Criteria for TMD. Participants were clinically examined and filled out a questionnaire in which selfreported psychosocial functioning was assessed on standardized measures, including the Youth Self-Report (YSR), somatic complaints, and stress. Results: No significant differences were found in dental factors among adolescents in the TMD group compared with those in the control group. Multiple pains in the body and fatigue were significantly more common in the TMD group compared with the control group. Adolescents with TMD also reported significantly higher levels of stress, somatic complaints, and aggressive behavior than their counterparts in the control group. In particular, young adolescents with TMD reported high levels of psychosocial problems. Conclusion: In adolescents with TMD, psychosocial factors such as increased levels of stress, somatic complaints, and emotional problems seem to play a more prominent role than dental factors. Keywords: adolescence, bruxism, headache, psychological tests, temporomandibular disorders

Aims: To estimate the prevalence of self-reported symptoms associated with temporomandibular disorders (TMD) and treatmentseeking in adult Chinese in Hong Kong. Methods: A telephone survey technique was used to identify 1,526 randomly selected Cantonese-speaking individuals aged 18 years or over. Standard questions were asked about joint and jaw muscle pain, jaw opening, and joint sounds. In addition, questions on tooth grinding and clenching, sleep patterns, and treatment-seeking behavior were posed. Results: Jaw pain was reported by 33% of the population. Only 5% of them had frequent pain, with two thirds of this subgroup having moderate to severe symptoms. The prevalence of frequent problems with jaw opening and joint clicking was 0.3% and 1.8%, respectively. There were no gender-related differences in the reporting of TMD symptoms or related conditions. Conclusion: One percent of the Hong Kong Chinese population had TMDrelated jaw pain that was of moderate or severe intensity and occurred frequently; 0.6% of the population had sought treatment for jaw pain, impaired jaw opening, or joint clicking that occurred often in the previous year. Keywords: temporomandibular disorders, epidemiology, prevalence, jaw pain

Aims: To identify predictors for anxiety and depression in orofacial outpatients and to investigate the patients' compliance rate in taking a series of psychologic tests. Methods: Three thousand six hundred sixty-six patients completed a battery of questionnaires. These consisted of items inquiring about sex, age, past history of disease, presence of pain, the Hospital Anxiety and Depression Scale (HADS), the Eysenck Personality Questionnaire Short Form (S-EPQ), a Japanese dental version of the McGill Pain Questionnaire (JDMPQ), a visual analog scale (VAS) of pain, pain duration, and diagnosis. After univariate analyses had determined those variables with significant differences between an over-probable group (OPG, HADS scores >= 8) and an absent group (AG, HADS scores 8), we estimated the odds ratios of these variables for OPG as independent variables, and every variable was adjusted between the independent variables by multiple logistic regression models. Results: For anxiety, 3 variables were independently related to the OPG and considered to be meaningful: age 30 or older, neuroticism score on the S-EPQ, and selection of the JDMPQ pain expression term "sickening." For depression, 4 variables were independently related to the OPG and considered to be meaningful: age 30 or older, neuroticism and extroversion scores on the S-EPQ, and selection of the JDMPQ pain expression term "sickening." The compliance rate for the tests was under half of the patients (3,666 of 7,542 patients). Conclusion: Although the predictability for anxiety or depression by some baseline parameters is considered to be low, age, personality traits, and choice of certain pain expression terms are useful predictors of anxiety or depression. The improvement of the compliance rate for psychologic screening will be a future challenge for Japanese clinics managing orofacial patients. Keywords: questionnaires, anxiety, depression, predictor, logistic model, regression analysis

Aims: Sleep bruxism, which is a form of orofacial motor activity (OMA), and jaw muscle pain and soreness have for a long time been thought to be mutually linked. The aim of this study was to investigate the effect of clinical and experimental jaw muscle pain and soreness on sleep OMA. Methods: Twelve healthy subjects aged 21 to 31 years old participated in this study. All of them were aware of signs or symptoms of sleep OMA and were subdivided into a group with clinical pain complaints (n = 5) and a group without pain (n = 7). All subjects slept in the laboratory for 3 consecutive nights, including a habituation night, a baseline night, and an experimental night. Electroencephalographic (EEG) activity and electromyographic (EMG) activity from the masseter muscles were recorded during sleep. On the experimental night, before sleep, all subjects received an injection of capsaicin (0.1 mL, 100 µg/mL) into the masseter muscle that had demonstrated the most EMG activity during the previous recordings. The OMA events and episodes were quantified and were compared between the baseline night and the experimental night. Every evening and morning during the study period, pain intensity, unpleasantness, and soreness were scored by the subjects on a visual analog scale (VAS), and pain detection thresholds (PDTs) in the masseter muscles and maximal voluntary occlusal force (MVOF) were also measured. Results: Pre-sleep injection of capsaicin did not cause significant differences between groups in peak pain intensity on the VAS. The PDT and MVOF did not show any significant differences between groups, injection and non-injection sides, or baseline and experimental nights and mornings. The number of EMG episodes/hour sleep, the number of bursts/hour sleep, and total area of all bursts and episodes during the baseline night were significantly higher in the subjects without pain than in the subjects with pain. However, the capsaicin injection did not cause any significant changes in these parameters. Conclusion: This study suggests that an acute pre-sleep painful stimulus does not have any effect on OMA during sleep, but the study extends previous findings that clinical jaw muscle pain and soreness are associated with less EMG activity in the masticatory muscles. Keywords: masticatory muscles, capsaicin, bruxism, pain detection thresholds, bite force, electromyography